Electric remote control system



Aug. 17, 1937. H. E. HUMPHREES El AL 2,090,205

ELECTRIC REMOTE CONTROL SYSTEM Filed May 17, 1935 2' Sheets-Sheet l (I) INVENTORS C "-1 HORACE EDGAR HUMPHRIES HENRY JOHN EDWARDS ATTY:

Aug, 17, 1937 H. E. HUMPHREES ET AL 2,090,205

ELECTRIC REMOTE CONTROL SYSTEM Filed May 1.7. 1955 2 Sheets-Sheet 2 I NVENTORS HORACE EDGARVHUMPHRIES HENRY JOHN EDWARDS Patented Aug. 17, 1937 UNITED STATES PATENT or fice ELECTRIC REMOTE CONTROL SYSTEM Application May 17, 1935, Serial No. 22,032 In Great Britain June 21, 1934 1'7 Claims.

The present invention relates to electric remote control systems and more particularly to such systems in which control is exercised by means of electric current impulses as, for ex- 5 ample, automatic telephone systems. The current impulses in such systems are ordinarily intermissions of direct current.

A desirable feature in such systems is an ability to transmit signals over the control circuit dur- 10 ing the transmission of ordinary trains of current impulses and receive and utilize the same. It mayalso be desired to transmit signals prior and/ or subsequent to an ordinary train.

. Ihe present invention has in View arrange- ]5 ments to this end and more specifically arrange ments in which the signals are themselves in impulse form. It will be appreciated that such arrangements would allow of the transmission of more thanv one trainof impulses simultaneousg ly or by the employment of suitable receiving apparatus, allow of special circuit changes being made at the receivingend prior to or subsequent to the transmission of an ordinary trainof impulses.

25 The ordinary rate of impulsing in electric remote control systems of the kind mentioned is comparatively low, of the order of 10 impulses per second. The signals utilized in thev present invention consist of circuit closures or interrup- S tions of a much shorter duration such as may be termed fleeting signals. Their duration is such as would be occasioned by the make through period of a make-before-break contact of arrelay adapted to receive ordinary impulses or by the 35 change over of a contact ofsuch a relay from its back to its front position or vice versa. The sig nals accordingly vmay have a duration of the order of 2 milliseconds.

For the generation of such signals various arrangements may be employed; for instance, if a signal has to be transmitted prior to the transmission of an ordinary train the off-normal contacts of a number dial may bring about closure of a charging circuit for a condenser inseries with 0 a relay,the relay operating by the charging current and. conscquently'opening and closing the impulsecircuit or again, in machine impulsing rotating cams; may give rise to a condition corresponding to the make through condition of a relay.

At the receiving end must be provided a relay capable'of responding to such fleeting signals such as a relay (hereinafter generically referred 5 tons a high speed relay) of the type described in Patent 1,992,610 of Ernest J. Gachet, issued Feb. 26, 1935. I

Since however ordinary impulses are to be received also, it is preferable that the slower relay which responds to the ordinary impulses and 5 controls switches accordingly should itself receive impulses repeated by the high speed relay (1. e. that receiving the fleeting signals).

Fleeting signals transmitted during anordinary train may be transmitted during the make periods of the ordinary train or during thebreak periods, the fleeting signals in the one case being a break, in the other a make. It is also possible to transmit fleeting signals during. the make and the break periods of an ordinarytrain.

It may also be arranged that anrordinary train of impulses may be transmitted but not utilized at any particular time the imulses to be utilized being in the form of fleeting signals.

The invention and a manner of carrying it into efiect will be clear from the following description" taken in conjunction with the accompanying drawings which show embodiments of the invention by way of example.

In the drawings Fig. 1 shows in diagrammatic form the makes and. breaks of impulses in a .train of impulses and the fleeting circuit closures and. interruptions contemplated in the present invention. Fig. 2 shows a methodof generating a fleeting circuit interruption by a number dial at.. the commencement of an impulse train! Fig.3

shows arrangements for recei'vingsignals comprising fleeting circuit interruptions. during the make portion of impulses of standard length.

"Fig. 4 shows a similar arrangement for receiving 3 j3fimpulse trains simultaneously. Fig. 5 shows how.3 simultaneous impulse. trains maybe transmitted and. Fig. 6 a time chart of the closures "of the cam contacts of Fig. 5 to facilitate the understanding of the transmitting arrangement. 40

. Fig. l'requires only a brief consideration. In

this figure time is' measured horizontally and current vertically. In (a) a series of impulses of current represented by the rectangles 0- are shown and in the interventing space or break "between two current impulses are shown two" 1 fleeting circuit closures or makes, the duration of these compared with those of standard impulses shown at C being apparent. In a similar and fleeting makes or circuit closures during the break periods of standard impulses Standard.

impulses may be taken to be of the order of 10 per second and with the ratio usually employed in automatic telephone systems, i. e. make: break::1:2 the duration of a standard pulse of current is of the order of 33 milliseconds. The duration of a fleeting signal on the other hand is of the order of 2 milliseconds.

A method of transmitting a fleeting break at the commencement of an impulse train will be 10 apparent from'Fig. 2. In this figure DK represents contacts of a dialling key such as may be used at a telephone operators position, or switch hook contacts on a telephone instrument, is be ing the impulse springs of the dial and on the 15 dial off-normal contacts. When the contacts DK are closed, a loop circuit is closed over contacts is and is. When the dial is turned off normal contact on closes and remains closed until the dial again reaches its normal position after trans- 20 .mitting a train of impulses. On the closure of contact on condenser Q is charged and relay TS is operated momentarily by the charging current. The time for which it is operated may be determined by the size of the condenser Q and 25 the impedances in shunt and in series with it, and

35 arrangements being assumed to be provided for the transmission of fleeting breaks during the transmission of a pulse of current in a train of standard impulses. In the upper part of the figure is shownin skeleton form the connection of 40 an impulse receiving relay S over contacts h of a switching relay (not shown) to the two speaking wires incoming to an automatic telephone selecting switch. The relay S and the corresponding resistance in the other wire may be taken asbe- 5 ing in a circuit available for use with any one of a number of similar selecting switches for itscontrol. Relay S is a high speed relay capable of responding to breaks of a very short duration,

e. g. of the order of 1 to 2 milliseconds. Of the 50 relays concerned with impulse and signal repeti- 60 and PB being high speed relays similarto relay S, and DM is a stepping magnet adapted to be operated in response to standard impulses repeated by relay A.

, The method of .operation of the apparatus. 5 shown in' response to standard impulses willfbe a parent from the following brief description.

When the two wires incoming to the upper part 'of the figure are looped relay S operates and at its single contact sl closes parallel circuits for relays A, B and c (winding (1)). A rectifier R is included in the circuit for relay B to prevent possible deleterious effect on the I release lags of these 'three'relays. RelayA operates quickly and opens a point in the circuit of magnet DM 7 at contact al and preparesa circuit for relay PB.

Relay B on operating closes a point in the circuit for magnet DM at contact b2 and a point in a circuit for relay P at contact bl. Standard impulses received by relay S are repeated at contact sl, relay A releasing during each break pe-- riod. Contact al on falling back closes the circuit for magnet DM which includes a holding winding (II) of relay C. The magnet operates and performs its stepping function either on the attraction or retraction of its armature. During 0 the break portion of an impulse, contact al being in its back position, relay P operates in a circuit from earth over contacts sl, bl, pbl, paZ, relay P, resistance, to battery. Contact pl closes but since contact al is in its back position and. relay P releases due to the change over of contact sl before relay A becomes fully operated no further circuit changes occur. If, during the time relay A is steadily operated by the make period of an impulse, or during the preliminary energization of relay A prior to impulsing a fleeting break occurs in the circuit of relay S, that relay responds to the break but owing to its very short duration relay A does not have time to release consequently contact al remains in its front position and the magnet DM is not energized. On the release of relay S by such an impulse relay P is operated as before and prepares at contact pl, a circuit for relay PB and winding (I) of relay PA. These relays are at this time short-circuited but immediately relay S re-operates relay PB operates in series with relay P which remains operated pendingoperation of the slower operating relay PA. Contact pbl disconnects back contact sl from the circuits shown within the dotted line rectangle and connects it over wire W to similar circuits the relays of which corresponding to PB and PA operation of relay PB relay PA operates in series with relay P and locks up over its winding (II) over contacts pa3, b3 and any other contacts which may be included in this circuit. Contact pal disconnects the operating circuits for relays PA and PB and contact paZ closes across the contacts pbl to maintain the signal circuit to wire 'W after the release of relay PB. It will now be clear that a further fleeting break signal during a period when relay A is steadily energized will pass a signal to a circuit connected to wire W which may be arranged so that a third fleeting break signal will pass to a third circuit and 'so on. The signals, by the operation of relays .such as PA and PB may be arranged to bring about any desirable operation. It will be appreciated that by connecting a similar receiving circuit to the front contact of sl signals trans-' .mitted as fleeting makes during the break porvtion of impulses may be received. Details of .such an arrangement are shown in Fig. 4 which 1 illustrates an arrangement for the reception of three impulse trains simultaneously.

Reference will now be made to Fig. 4. In this figure relays A, B and C perform functions similar to those performed by the correspondingly designated relays in Fig. 3. Contact sl is a'conx tact of a relay which corresponds to relay S in P Fig. 3, relays P and PP correspond to relay P L and relays QB, QQB and QM and QQM are responsive to fleeting breaks and makes respectively and are of the high speed type. Relay CA is provided to take care of the case in which there are fewer standard impulses than fleeting makes and breaks. The standard impulses bring about the operation of magnet SDM and the fleeting makes and breaks the operation of magnets MDM and BDM respectively. Rectifiers HI and R2 are provided for the reason previously give-n.

The operation of magnet SDM by standard impulses will now be described. On the closure of a loop circuit, contact sl, by the operation of a relay such as S in Fig. 3, completes circuits for relays A, B and C (winding (1)). Contact (:02 opens a point in the magnet circuit and contact a3 disconnects winding (II) of relay C. Contacts bl and cl close in the magnet circuit and also prepare a holding circuit for relay C during impulsing. Standard impulses operating contact sl bring about the intermittent de-energization of relay A which accordingly releases and re-operates as contact sl falls back and comes up again. Since contacts al and sl always occupy corresponding positions under the impulsing conditions now being considered, relays QB, QQB, QM and QQM will not be operated but prior to impulse reception and during impulse make periods relay P will be operated and during impulse break periods relay PP will be operated. These relays ergized in a circuit from earth over contacts cl,

bl, cbl, a2, magnet SDM to battery and winding (II) of relay C is energized by the closure of contact a3. When magnet SDM has stepped its stepping switch from normal, contact so-n opens and relay C remains operated depending on pulses of current in its winding (II). It will release at the end of the impulse train due to the continued energization of relay A. v

If, during impulsing, fleeting breaks take place during a make period of an impulse, contact sl will respond to the signal but the condition of relay A will not be changed. Consequently on contact sl falling back, relay PP operates and prepares a holding circuit for itself at contact ppl and when contact si re-makes relay PP is scription that a fleeting make. occurring during the break portion of an impulse will bring about a like operation of relays P, QM and QQM and acorresponding operation of magnet MDM. It will be noticed that relays QQB and QQM are not operated until contact sl has revertedto the position it should occupy due to standard impulsing consequently no circuit is closed for relay CA. If the number of fleeting signals is less than the number of standard impulses no iurther fleeting impulse action will occur and no circuit will -be closed for magnets BDM and MDM after the be provided to prevent undesired operation of magnet SDM by the standard impulses which must be transmitted in order to provide a carrier for the fleeting signals. The prevention of operation of magnetfSDM in such circumstances is brought about bythe transmission of a special signal; This signal consists of two fleeting signals transmitted during the appropriate" period of the last standard impulse to be utilized the signal being makes or breaks depending on whether one of the corresponding'magnets has already ceased operation 'or not. If fleeting signals for the operation of magnet BDM have already ceased but fleeting makes are "to be transmitted for the further operationof magnet MDM then, during the standard' irnpuls'e break two fleeting makes are transmitted in succession the second being v transmitted lwithini-h'e "operating period-of the correspondingmagnet? The first of these tran' sient makesbrings about the operation of relays P, QM and QQM andthe second arriving before the magnet MDM'has" fully energized and opened contact mdm, earth is connected over contact sl, rectifier Rl, oontacts'bB, c3, qqm-l relay CA to battery. Relay CA- o'per ates and locks up over 'contacts'cal, rectifier R3;'contacts a2, cbl, bl and cl. When the standard impulse break is completed relay A rte-operates and at contact a2 removes a short circuit from relay CB which there'- upon operates in se'rieswith relay CAand remains operated for the remainder of the impulse train.

Further release of relay A'is thereby rendered ineffective as regards magnet SDM as the magnet circuit is open at contact cb'l.

If, on the'other' hand, signals for-the operation of magnet MDM have already ceased'but fleeting breaks are to' continue beyond the number of standard impulses required, then during the periodwhen relay A is'operated afterthe last operation of magnet SDM-two fleeting breaks are transmitted in s'uccessi'onthe second being transmitted Within the operating period of mag net BDM and thus" relay CA is operated by the second signal in "a 'c ircuit fror'n earthover contacts sl, b2,"c2"andqqb='l; Relay A being'already energized, relay' CB operates in series with relay CA on the removal of the shortcircuit across it by the return of -contactisl toits front position and opens the circuit of magnet/SDM at contact cbl Thus further release of relay 'A-will be without effect on magnet SDM butk'relay' C will be maintained:

If both kinds of fleeting signals are'to continue beyond the number of 'standard impulses then the double signal will be transmitted during the break period of thelast standard impulse break.

Another method which may be employed to;

prevent operation of magnet SDM by impulses transmitted for the purpose of carrying the fleeting signals and to hold relay C until the last impulse has been receivedisto transmit a long train of impulses, the first l 0 of which are merely for the purpose of carrying-the fleeting signals, assuming III to be the maximum number required, the remainder of the train containing as many impulses a's' maybe necessary to operate magnet SDM to steptheswitch to the required contacts. Contact a2 may 'normally *be effective 'to'cause the switch operated by magnet SDM to take l0'steps and in a ddition further steps depending on the digit transmitted, by this means no special signal signifying the end of the fleet ing impulse trains will be necessary.

'A method"of-transmitting the fleeting signals will now be described with reference to Figs. 5 and 6. Fig. 5 shows somuch as is necessary of 'a register sender circuit in an automatic teleand S4.

phone system for the understanding of the invention, the general. operation of such a circuit being well known to those skilled in the art of automatic telephony. In this figure it is proposed to transmit the hundreds, tens and units digits simultaneously, the hundreds digit being transmitted as fleeting breaks during the make period of standard impulses, the tens digit being transmitted as fleeting makes during the break period of standard impulses and the units digit being transmitted as standard impulsesr Of the apparatus shown SDM is the reverse drive sending switch magnet, wipers of the sending switch concerned with marking to determine the end of an impulse train being designated SI, S2, S3 Wipers H, T, and UI, U2, are wipers of the hundreds, tens and units digits registers which are set in accordance with the digits to be transmitted and mark appropriate contacts in the banks of the sending switch. Corresponding contacts in the banks of wipers UI and U2 are connected to contacts in the banks of wipers S3 and S4 so that for a given position of wipers UI and U2 the contacts marked in the bank of wiper S3 is one later in the direction of rotation of the switch than that marked in the bank of wiper S4. Relays TA and TB and TC are concerned with the termination of impulse transmission of the three digits respectively and when operated lock up over their left hand windings, and CO is the relay operated at the end of impulse transmission to bring about the release of the register controller. Relay IG is the guard relay to guard against a split first impulse being transmitted. Contacts OCH-C05 are cam operated contacts which are operated in. a cycle for the transmission of impulses and fleeting signals and for advancing the sending switch step by step. The times of circuit closure due tothelr operation in a cycle are shown diagrammatically in Fig. 6 to which a brief reference will now be made. In this figure time is measured horizontally and the period during which eifective circuit closure by a cam contact occurs is indicated by a horizontal line against the contact designated at the left of the figure; The diagram has been divided by vertical lines to show the make and break periods of standard impulses. It will be seen from the figure that the make portion of an impulse is provided for by the closure of contacts CC3 and during this time the lower contacts CC4 and upper contacts CC5 are closed all these contacts being open during the break portion of an impulse during which time magnet SDM is energized. It will also be seen that during the break portion of an impulse contact C02 which is shown as a make-before-break contact, is operated to give a fleeting make and the circuit over it remains open thereafter when the contact has changed from its-back to its front position. The make through period of the contact is too short to have any operative efiect on an ordinary impulse receiving relay but will operate a high speed relay connected to wires II and I2. Its return may take place during the period when contact C03 is closed so that it is ineffective or it can waittill the time when the next fleeting make is required when it can by its restoration provide the required fleeting impulse. Similarly contact CCI efiects a fleeting break by openingfor a very short period during the impulse make period.

When impulse transmission over the wires ll, I2 is to commence, contact at is closed by some relay TC over cam contacts CO5.

succession. This takes place as follows. wiper S4 is stepped on to the contact marked over wiper U2 the upper contacts CC5 are closed suitable means and a loop thereby completed over wire H contacts ig2 and a: and wire I2 and the distant impulse receiving relay is energized. A relay having contacts ss is also energized and the next time a short circuit across relay IG is removed by the opening of the upper contacts 004, the relay operates in a circuit over contact ssl to earth. Contact igl changing over prevents a reimposition of the short-circuit, and on the next closure of the upper contacts- CO4 magnet SDM is operated. It is subsequently released to advance the stepping switch one step. This action occurs at each closure and opening of the upper contacts CC4. Contacts 2'93 and ig4 prepare circuits for relays I'A and TB dependent on wipers SI and. S2 and contact ig2 changing over leaves the impulsing loop dependent on contact CC3. Contact 882 closes an operating circuit for Neglecting for the moment operation of contacts CCI and CC2 and relays TA and TB, it will be seen that each time contact CC3 opens the loop circuit is broken and an impulse break is transmitted enduring for the standard period to allow the distant relay, such as relay A in Fig. 3 responsive to standard impulses to release and perform its function, this relay being impulsed by a repeating relay such as relay S. Reference to Fig. 6 will show however that the operation of contacts CCI and CC2 will have the effect of transmitting fleeting makes and breaks during the break and make periods of the standard impulses, the loop circuit closed over contact C03 being opened transiently at contact CCI and when the loop circuit is open at contact CC3 a fleeting closure of the circuit will occur on the make through of contact CC2.

When the sending switch in the course of its stepping reaches a position in which earth is found on the bank of wiper SI over contacts ssl, upper contacts 004, igl, ig3 and wiper H, relay TA operates over its right hand winding and locks up over its left hand winding. Contact tal short-circuits contacts CCI and tcl so thatno more transient break signals are transmitted. Similarly relay TB is operated when wiper S2 encounters a contact earthed over contacts ssl, C'C4, 1'94 and wiper T and opening contact tbl prevents any further fleeting closures of the loop circuit by contact CC2.

When wiper S4 is stepped onto the contact marked over wiper U2 and assuming for the moment that relays TA and TB have been operated, relay TC operates from earth over contacts ss2, CO5 lower, m3 and tb2 and the marking circuit and at contact 2503 completes a circuit over contacts m4 and H73 for winding (I) of relay CO. Contacts tcl and tc2 are ineffective as regards the impulsing loop in the assumed circumstances.

If there are fewer impulses in the units digit than there are in the tens or hundreds-digits, then relay TC operates from earth over contact ss2, 0C5, M2 or tb2 depending on whether TB or TA has been operated. This takes place as follows. If relay TA has already operated but relay TB has not and there are more fleeting makes to be; sent, two fleeting makes are transmitted in When and when the next standard break commences these contacts are changed over and a circuit is completed over contacts ss2, CC5 lower, tb2, wipers U2 and S4 for relay TC. Before relay TC has time to operate fully contacts CC2 change over and transmit a fleeting make and this is followed very shortly by the change over of contacts tc2 which transmit a further fleeting make. The result of this is to render the stepping switch responsive to the standard impulses at the receiving end of the loop ineffective as will by this time have been understood from the description given of the operation of the circuits shown in Fig. 3. Further fleeting makes are sent by the operation of contacts CCZ during the break period of non-effective standard impulses. Similarly, if relay 'I'B has been operated but relay TA has not and further fleeting breaks are to be transmitted two fleeting break impulses are transmitted in succession. This takes place as follows: When the last standard impulse break to which response is required has been transmitted and the succeeding make period commences wiper .S3 is stepped to the contact marked over wiper UI and since the upper contact 0C5 is now closed relay TC operates in a circuit including this contact and contact m2. Before relay TC has fully operated contact CCI has transmitted a fleeting break in the loop and this is followed by a further fleeting break due to the change over of contact tcl with the result that the magnet responsive to standard impulses is rendered unresponsive to further standard impulses. Further fleeting breaks are transmitted until wiper SI encounters the contact marked over wiper H whereupon relay TA operates. Contacts m4, i193,

tc3 being now closed relay CO operates.

the loop closed until the hominghas been com- 'ple'ted and the register controller is released.

Relay 00 may be held operated until all the switches in the register controller have reached their home position by the closure of a circuit for its second winding over wire 1.

We claim:

1. In a control system, an impulsing circuit, means for transmitting current impulses over said impulsing circuit by opening and closing said circuit, means for transmitting signals over said impulsing circuit by fleeting interruptions oi the impulsing circuit during the imp-ulsingperiod in which the impulsing circuit is closed, and means for transmitting other signals over said impulsing circuit by fleeting closures of the impulsing circuit while said impulsing circuit is open during impulse transmission.

2. In a control system, an impulsing circuit, means for simultaneously transmitting more than one impulse train over said impulsing circuit, one impulse train comprising make and. break impulses of the ordinary duration of said impulsing circuit, the other impulse train comprising fleeting closures of said impulsing circuit during the break period of said one impulsing train, and receiving means for diiierentiating'between'the ordinary and fleeting impulse trains and operated in accordance therewith.

3. In a control system, "an impulsing circuit; means for transmitting ordinary impulses over said impulsing circuit by opening and closing said circuit; means for transmittingsignals over said impulsing circuit prior to, subsequent to,- or duringimpulse transmission, each signal comprising a fleetingcircuit interruption of said impulsing circuit during the period said impulsing circuit is closed; apparatus at a receiving point operative dicativeof an impulse.

4. In a control system, an impulsingcircuit, means for transmitting ordinary impulses over said impulsingcircuit by opening and closing said circuit, means for transmitting signals over said impulsing circuit, each signal comprising a fleeting circuit interruption of said impulsing circuit during the period said impulsing circuit is closed, a high speed relay at a receiving point operated in response to each signal and each impulse for repeating said impulses and signals, an impulse relay controlled by said high speed relay and operated only in response. to said repeated impulses, and a second high speed relay controlled by said first high speed relay dependent upon the operated condition of said impulse relay.

5. In a control system as claimed in claim 3 wherein the signal transmitting means includes a contact spring set in the impulsing circuit having its front contact electrically connected to its back contact and a moving part which produces a fleeting circuit interruption by the change over from its back contact to its front contact when operated.

6. In a control system as claimed in claim 2 wherein said receiving means includes a relay responsive to both said ordinary impulses and said fleeting closures, a second relay controlled by said first relay and responsive only to said ordinary impulses, a third relay controlled by both said first and second relays and responsive only to said other impulse train, a plurality of pieces. of apparatus operated in accordance with the simultaneously transmitted impulse trains, and contacts on said second andjthird relays for operating said apparatus.

'7. In a control system, an impulsing circuit, means for simultaneously transmitting more than one impulse train over said impulsing circuit, one

"impulse train comprising make and break imand means. for preventing the operation of said first apparatus in response to ordinary impulses when such impulses are transmitted only forthe purpose of providing means for transmitting the fleeting interruptions in-said other'impulse train.

8. In a control system as claimed in" claim 7 wherein said preventing means includes a relay operated in response to receipt of two'successive fleeting signals of the same nature in case the second of said signals is. received before the first has been fully responded to.

9. In a control system, an impulsing circuit, means for simultaneously transmitting more than one impulse train over said impulsing circuit; one impulse train comprising a fixed number'of 'im-,

imposed on the break impulses of said fixed number of impulses, a first and a second apparatus, means responsive to said other impulse train for operating said second apparatus in accordance with the fleeting closures in said fixed number of impulses, and means responsive only to said variable number of ordinary transmitted impulses for operating said first apparatus in accordance with the number of ordinary impulses in said I variable number.

10, In a telephone system, an impulsing circuit, a sending switch for transmitting trains of impulses, bank contacts in the bank of said switch corresponding in number to the number of impulses in the longest single impulse train I required to be sent, a register for marking certain of said bank contacts in accordance with a plurality of recorded digits, means including said switch'and said marked bank contacts responsive to a single rotation of said switch for simultaneously transmitting a plurality of impulse trainsover said impulsing circuit in accordance with said recorded digits, one of said impulse trains comprising make and break impulses of the ordinary duration of said impulsing circuit, andanother of said impulse trains comprising fleeting interruptions of said impulsing circuit superimposed on the make impulses of said one impulse train.

11. In a telephone system, an impulsing circuit, a sending switch for transmitting trains of impulses, bank contacts in the bank of said switch corresponding in number to the number of impulses in, the longest single impulse train required to be sent, a register for marking certain of said 50 impulse trains comprising fleeting interruptions of said impulsing circuit superimposed on the make impulses of said one impulse train, cyclically operated contacts for transmitting said fleeting interruptions during the make periods of the 55 impulsing circuit, wipers on said switch operative to engage said bank contacts, relays connected to said wipers and operated responsive to the corresponding wipers engaging its marked bank contact, and means controlled by said relays 60 when operated for disabling said cyclically operated contacts to transmit further fleeting interruptions of said impulsing circuit.

12. In a telephone system, an impulsing circuit, a sending switch for transmitting trains of 65 impulses, bank contacts in the bank of said switch corresponding in number to the number of impulses in the longest single impulse train required to be sent, a register for marking certain of said bank contacts in accordance with a plu- 70 rality of recorded digits, means including said switch and said marked bank contacts responsive to a single rotationof said switch for simultaneously transmitting a plurality of impulse trains over said impulsing circuit in accordance with 76 said recorded digits, once]? said impulse trains comprising make and break impulses of the ordi nary duration of said impulsing circuit, another of said impulse trains comprising fleeting closures of said impulsing circuit superimposed on the break impulses of said one impulse train, cyclically operated contacts for transmitting said fleeting closures during the break periods of said impulsing circuit, wipers on said switch operative to engage said bank contacts, relays connected to said wipers and operated responsive to the corresponding wipers engaging its marked bank contact, means controlled by said relays when operated for disabling said cyclically operated contacts to transmit further fleeting closures of said impulsing circuit, receiving apparatus operated in accordance with said transmitted impulse trains, means controlled by a particular one of said relays if operated before the other of said relays, for transmitting an additional fleeting signal immediately before or after the signal of the same nature transmitted by the cyclically operated contacts, and means for disabling said receiving apparatus in response to the receipt of said additional transmitted fleeting signal.

13. In a control system, an impulsing circuit, means for transmitting ordinary impulses over said impulsing circuit by opening and closing said circuit; means for transmitting signals over said impulsing circuit prior to, subsequent to, or during impulse transmission; each signal comprising a fleeting circuit closure of said impulsing circuit during the period said impulsing circuit is open, apparatus at a receiving point operative in response to the receipt of said impulses and signals, and means for preventing the operation of said apparatus to record a fleeting signal in case the circuit closure persists for a period indicative of an impulse.

14. In a control system as claimed in claim 13 wherein the signal transmitting means includes a 15. In a control system, an impulsing circuit,

means for transmitting ordinary impulses over said impulsing circuit by openingand closing said circuit, means for transmitting signals over said impulsing circuit prior to impulse transmission, each signal comprising a fleeting circuit interruption of said impulsing circuit, apparatus at a receiving point operative in response to the receipt of said impulses and signals, means for pre venting the operation of said apparatus to record a fleeting signal in case the circuit interruption persists for a period indicative of an impulse; said signal transmitting means including a condenser, a relay and means for charging said condenser to momentarily operate said relay to transmit a fleeting signal.

16. In a control system, an impulsing circuit, means for transmitting ordinary impulses over said impulsing circuit by opening and closing said circuit, means for transmitting signals over said, impulsing circuit prior to impulse transmission, each signal comprising a fleeting circuit interruption of said impulsing circuit, apparatus at a receiving point operative in response to the receipt of said impulses and signals, means for preventing the operation of said apparatus to record a fleeting signal in case the circuit interruption persists for a period indicative of an impulse; said signal transmitting means including a condenser, a relay connected in series with said condenser, a source of current, and off-normal springs on a number dial to charge said condenser from said source to momentarily operate said relay to transmit a fleeting signal.

1'7. In a control system, an impulsing circuit, means for simultaneously transmitting more than one impulse train over said impulsing circuit; one impulse train comprising make and break impulses of ordinary duration of the impulsing circuit, the second impulse train comprising fleeting l0 circuit interruptions of said impulsing circuit superimposed on the make impulses of the first impulse train, and the third impulse train comprising fleeting circuit closures of said impulsing circuit superimposed on the break impulses of the first impulse train; and a first, a second and a. third apparatus operated in response to said three impulse trains. 

